Switchboard lamp



E. A. BOHLMAN SWITCHBOARD LAMP Filed Feb. 14 1921 Y 7 strip. of myinvention associated with a lamp Patented @et 2, 1923.

- nutren srarss raar ,essie ERNEST A. BOHLMAN, or orrrcAeO, rLLrNOIs,AssrGNon'ro KELLOGG- swITonBoAnn AND SUPPLY COMPANY, or cHrcAGO,rLLINors, A CORPORATION or rLLINors.v Y,

SVIITCHBOARD LA MP.

'Application filed February 14, 1921. Serial No. 444,772.l

To all whom t 'may concer/rt.'

Be it known that I, ERNEST A. BOHLMAN, a citizen of the United States ofAmerica, residing at Chicago, county or" Cook, and State ot Illinois,have invented certain new and useful ImprovementsV in Switchboard Lamps,of which the following is a specication.

My invention relates to switchboarf lamps which are small in size andadapted to be mounted within small confined spaces. These lamps areusedto a large extent for telephone switchboards and are mounted in banks.Switchboard; lamps et the above type are provided with terminal stripstowhich the lead-in wires of the lamps are soldered, and these terminalstrips contact with springs in the lamp jacks when a lamp is insertedtherein to connect a lamp in the circuit in which it is desired toinclude it.

An object of my invention is the provision of an improved terminal stripfor a switchboard lamp and means for' mounting the same, which is veryeconomical to manufacture, very simple in construction and the use of itgreatly facilitates the assembly oi the lamp, thus materially decreasingmanufacturing cost.

For a more complete understanding of my invention, reference may be hadto the accompanying drawing, in which like reference characters in theseveral views denote like parts, and in which Y Figyl is a perspectiveview of a'switchboa-rd lamp embodying the improved termina-l strip of myinvention;

Fig. 2 is a disassembled perspective view of the lamp bulb, the lampterminal strips and the base for the said lamp;

nal strips secured to the base of the ksaid lamp, andbefore the lampbulb is inserted betweenfthe termina-l strips; t Fig. 4 is -an enlargedsectional view of the fr lamp, illustrating the terminal strips securingmeansgrand Fig. 5`is a sectional view along theline 5 5 ofFig. 4. A

Referring now more in detail to my invent-ion as illustrated, I sho-wthe terminal bulb L, which is preferably of the form shown in which the.end oi the bulb is round. rIhe usual iilament 2 is provided and isconnected to and carried out through the side Fig. Sis a perspectiveview of the termiinsane walls of the lamp bulb L inthe usual man,-

ner by mea-ns of platinum wires,fthe ends v3 and 4 lof said wires beingsoldered to theV terminal strips 5 5. The Vmetallic contact strips orterminal strips 5 5 forming ter-` minals of the lamp arelpreferablyfofthe form shown that is, they extend along the sides of the bulb L forsome distance and are suitably Vshaped for aportion of their length tocause them to' closely fit the contour of the lamp, bulb L. rIheterminal strips 5 5 are suitably cut and stamped of sheet brass, and asboth terminal strips are similarly constructed, a description of onewill be sufficient. Y v j A wooden base 7 is provided, whosebody portion8 is cylindrical in shape, and its end 9 is beveled for purposes as willpresently be described. The base 7 is provided with a central opening 10extendingI the length of the base 7 and is 'of a size to receive thereduced end portion 11 of the bulbA L; the

said base 7 also serves as a mounting means for the terminal strips 5 5.Y The terminal strip 5 comprises a forwardly extending portion 6,suitable in shape to cause it to iit 'closely to the lamp bulb L, anditsrearward V.beveled portion 13 of the terminal strip5. The terminalstripl 5 isalso provided with a pair of clips 15, integrally formedtherewith, vthe said clips 15 `being intermediate` of the ends of theterminal strip 5 andbein for purposes asfwill presently be describe Tosecure'the terminal strip 5to thebase .7, -therearward portion 12 or thevterminal vstrip 5 is placed over tlieicylindrical and beveled portions8 an'd9 of the base .7 and slipped forward to cause thevt'ongue 14 of 5tov enter the centralopening -10 of the base 7. When in this position,as illustrated .the end -ot thefbase 7 and the V-clipsl 15l are bentover .the edge of. and into therhollow,vv

10o the beveled portion18 of the terminal strip base 7 and'iirmlyengagenthe circumferf 'Y entia-l edge 16 of the cylindrical portionofthe-base 7, as clearlyy illustrated in Figs. 4 and 5. The said clips 15,in association i. movement of the terminal strip in relation to the base7, and this method of securing Valso prevents side movement of theterminal strip,*thus producing a `rigid mounting of the said terminalstrip to the base 7. vThe terminal strip 5 is also provided with anintermediate reduced .portion 17, and the inner face 18 of theV reducedportion 17 forms a; soldering face to which the platinum terminals 3 and4 of the lampi-ilament are soldered.` rlhe terminals 3 and l aresoldered to the face 18 and near the edge of thel respective terminalstrips, there be'- -ing sufficient space between the reduced end of thelamp bulb L and terminal strips 5-,-5 to Apermit the soldering of saidterminals to said terminal strips.

l/Vhe'n kthe terminal strips 5-5 are secured to the base 7, as `justdescribed, the forward 'end portions 6-6 converge, as clearlyAillustrated in Fig. 3, and when the terminal ist-rips 5-5 are thusassembled to the base 7 Vtheyare ready to receive a lamp bulb L. A lampvbulb L isinserted between the end Yport-ions. 6 6 of the terminalstrips 5--5/Y with -redu'ced'end vportion 11 of the bulb L 'resting inthe central opening 10 of the base 7. A suitable cement is placed on theend 11 of the lamp bulb L to secure said bulb Yto the' base 7. Cement isalso placed on the yinner surfaces. of the forwardly extending` portions6 of the terminal strips 5 to secure a lamp -bulb L to the terminalstrips. In the former methods clamping means are ,provided to hold thebulbs in place between 'the terminals between the time that theVcei'nent'is placed thereon until it has hardened by means of a dryingoperation, but with a terminal' of my construction this clamping' meansis eliminated, as the bulb Lwhen inserted between the two terminal stripVends 6 forces the free ends against their normal tension, and thistension Vof the terminalstrip ends holds the Vbulb L in place withoutany holding means during theV 'drying operation.

,l Thel ends 6 of the terminal strips 5 of `vthe 'assembled :lamp areadapted to be en- :ga'ged by contact 4springs of the lamp sockets, thelatter being usually in the form oflamfp jacks comprising a pair ofsprings Y Vas iswell understood in theart, and 'a por- -tion of thisen'd6 of theV terminal strip 5 Vis provided with a flattened ,surfaceV 21 to`.Y'provideag'ood contact surface between the e saidlstermi'nal strips5- 5 :ofthe lamp and theccntact springs of lamp sockets, and this Yfiath'ess tendsfto prevent the lamps from be- 60 ing turned out voftheir prosper position during'their insert-iomor thereafter; The beveledportionsfldof the terminal strips 5, for'm wedge facesse that when thelamp as a whole is inserted between the spring terminals of the lampjacks, it causes the Meegos said contact springs of lthejaclrv to bespreadV apar'L to 'permit the ready insertion 'of the said lamp. Thebase 7 is provided with a pair of ribs 22 'diametrically opposed, forthe usual purposes of 'separatien between the two terminal strips 5-5secured to the base 7.

From the foregoing it is apparent 4that l have provided a terminal stripwhich is simple, complete and efficient in association with a.switchboard lamp, and it has been described with reference to aparticular lamp construction, but it is readilyseeiiV it is applicablefor other forms ofV lamps,

and that changes will readily suggest therm-` selves, and l, therefore,do not wish to be limited to the exact structure asshown and described,but aim to cover all such changes and modifications as come within thespirit and scope of the appended claims. Y

Having described myl invention whatl claim as new and desire to secureby Letters Patent is:

1. A terminal. strip of the 'class described'l comprising` a forwardlyextending portion and an enlarged rear portion, artongue integrallyformed with the rear portion of and j parallel'to said terminal strip',aV base pro# vided with a central orifice for receiving the.,4

tongue to position said terminal upon said base, a pair of clipsintegrally formed with said rear portion whereby said terminal stripengages the other end of said base, said clips engaging saidorilice insaid other end in the same plane with said tongue. Y

2. A terminal stripV of the class described comprising a forwardlyextending portion and an enlarged rear portion, a. tongue sheared out ofthe rear portion of said terminal strip, a base provided with a centralorilice for receiving said tongue to position said terminal strip uponsaid base, a pair of means integrally `formed withsaidr enlarged rearportion and -intermediate of said terminal strip ends, 'said pair o=f'means turned baclrto engage said orice for securing said terminal stripupon said base. j l,

3. A terminal strip of the class described comprising a forwardlyextending portion and a rear portion, an angularly Ydisposed tonguesheared out ofthe rear-portion of said terminal strip, al base .providedwithV a Vcentral orificeV into which 'said ltongue eX tends Yforpositioning said terminal stripy orifice in saidbase for-securingsaidterminal strip to said base, another -tei'minal"istrip' mounted on saidbase like the jfirst, and a pair of non-conducting flangesv on saidvbase separating said terminal strips.

4;. A terminal strip of the class describedY comprising a forwardlyextendingV portion and a rear portion, an angularly disposed tongueintegrally formed on said rear portion, a base provided with a Ycentra-1orifice into which the said tongue extends, and a pair of clipsintegrally formed intermediate of the ends of said terminal strip bentto engage said forward end of said base to secure said terminal strip tosaid base, said base having a pair of non-conducting flanges and saidterminal strip having its rear portion shaped to substantially conformwith the contour of said base whereby said terminal strip engages saidflanges to align said terminal strip, and to preventsaid termi* nalstrip from rotating on said base.

5. A terminal strip of the class described comprising a forwardlyextending and a rear portion, saidk rear portion having beveledportions, a tongue integrally formed with one of said beveled portionsand a pair of clips integrally formed with the other beveled portionsintermediate of the ends of said terminal strip, a base having its oneend beveled and provided with a central orifice for receiving saidtongue to position the said terminal strip upon said base and said clipsbent to engage the circumferential edge of the forward end of said'baseto secure said terminal strip upon the base aga-inst lineal movement,and a pair of flanges for said base, said beveled portions carrying saidclips engaging said flanges to prevent rotation of said terminal stripupon sai base.

6. In an electric lamp terminal strip, a base element, said terminalstrip having a tongue sheared out of its body near its rear end forextending into said base member, a

pair of flanges integrally formed with said rear end of Vsaid terminalstrip for engaging -said base element to prevent rotation of saidterminal strip on said base element, and a pair of' clips betweenitsends turned over to clamp said base member.Y

7. In a pair of electric lamp terminal strips provided with Vflangedportions, a non-conducting cylindrical base provided with an orifice andalso having flangesto engage said flange portions of said terminalstrips to insulate and align the said terminal strips, and three clipson each terminal strip to engage the orifice in said base on oppositesides of the flanges, part of said clips at the end of the terminalstrips and part at interl mediate points thereof, said clips securingsaid terminal strips to said basje against line-al movement and saidflanges engaging said flange portions to also prevent rotatable movementof said terminal strip.

8. In an electric lamp, a base of non-con-v duct-ing material in theform of a flanged cylinder beveled on both sides at the rear end, andterminal strips each having beveled ,i

side portions and a beveled end portion forv engaging the flangedbeveled portions ofv said base, and mounted thereon each beveled endportion of said terminal stripshaving one clip to engage the rear end ofthe base and each beveled side portion of said termiward end.

Signed by me at Chicago, in the county of Cook and State of Illinois,Ythis 11th day of February, 1921. y i

ERNEs'r A. BOHLMAN.

nal strips having a clip to engage the orp

